Systems and methods for shunting fluid

ABSTRACT

Systems and methods are provided herein that generally involve shunting fluid, e.g., shunting cerebrospinal fluid in the treatment of hydrocephalus. Self-cleaning catheters are provided which include split tips configured such that pulsatile flow of fluid in a cavity in which the catheter is inserted can cause the tips to strike one another and thereby clear obstructions. Catheters with built-in flow indicators are also provided. Exemplary flow indicators include projections that extend radially inward from the interior surface of the catheter and which include imageable portions (e.g., portions which are visible under magnetic resonance imaging (MRI)). Movement of the flow indicators caused by fluid flowing through the catheter can be detected using MRI, thereby providing a reliable indication as to whether the catheter is partially or completely blocked.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 61/755,018 filed on Jan. 22, 2013, which is hereby incorporated herein by reference in its entirety.

FIELD

The present invention relates to systems and methods for shunting fluid, e.g., shunting cerebrospinal fluid in the treatment of hydrocephalus.

BACKGROUND

Shunt systems for transport of body fluids from one region of the body to another region are generally known. For example, shunt systems are often used in the treatment of hydrocephalus to drain excess cerebrospinal fluid (CSF) from the ventricles of the brain. A typical shunt system includes a pressure-sensitive valve that is implanted beneath the skin. A ventricular catheter extends from one side of the valve to the ventricle. A drain catheter extends from the other side of the valve to a drain site, such as the abdominal cavity.

After implantation and use over extended time periods, shunt systems tend to become clogged in certain individuals. Clogging can occur due to foreign materials which collect in the narrow tubular passageways of the shunt system and in the inlet and outlet openings of such passageways. Consequently, it is often necessary to perform follow-on operations on an individual to remove the clog or replace the entire system. The inconvenience, cost, and risk of complications associated with these follow-on procedures are considerable and undesirable. Accordingly, a need exists for improved systems and methods for shunting fluid.

SUMMARY

Systems and methods are provided herein that generally involve shunting fluid, e.g., shunting cerebrospinal fluid in the treatment of hydrocephalus. Self-cleaning catheters are provided which include split tips configured such that pulsatile flow of fluid in a cavity in which the catheter is inserted can cause the tips to strike one another and thereby clear obstructions. Catheters with built-in flow indicators are also provided. Exemplary flow indicators include projections that extend radially inward from the interior surface of the catheter and which include imageable portions (e.g., portions which are visible under magnetic resonance imaging (MRI)). Movement of the flow indicators caused by fluid flowing through the catheter can be detected using MRI, thereby providing a reliable indication as to whether the catheter is partially or completely blocked.

In some embodiments, a catheter for shunting fluid built up within a skull of a patient is provided that includes an elongate tubular body having proximal and distal ends, first and second flexible tips extending from the distal end of the elongate body and having one or more fluid passageways extending therethrough, a plurality of fluid ports formed in the first and second tips, and a coupling member configured to hold the first and second tips in a position adjacent to one another.

The first and second flexible tips can be sized and configured for placement in a brain ventricle. The coupling member can be or can include a peelable sheath disposed around the first and second tips. The coupling member can be or can include a seamlessly removable insertion sheath disposed around the first and second tips. The coupling member can be or can include a bioabsorbable adhesive disposed between the first and second tips. The coupling member can be or can include a stylet or cannula disposed around the first and second tips. The first and second tips can each have a D-shaped cross-section. The first and second tips can together form a circular cross-section when coupled to one another by the coupling member. The first and second tips can each have a circular cross-section. The plurality of fluid ports can be formed in a helical pattern through sidewalls of the first and second tips. Pulsatile flow of fluid in which the first and second tips are disposed can be effective to cause the first and second tips to strike one another, thereby dislodging obstructions from the first and second tips. The catheter can include a plurality of shrouds, each shroud being disposed over a respective one of the plurality of fluid ports. The plurality of shrouds can be formed as hollow quarter spheres.

At least one of the first and second tips can include an embedded microsensor. The embedded microsensor can be or can include at least one of an interrogatable sensor, a pressure sensor, a tilt sensor, an accelerometer sensor, a glutamate sensor, a pH sensor, a temperature sensor, an ion concentration sensor, a carbon dioxide sensor, an oxygen sensor, and a lactate sensor. The embedded microsensor can be or can include a pressure sensor that supplies an output indicative of a pressure in the environment surrounding the first and second tips to a valve to control a fluid flow rate through the valve. At least one of the first and second tips can contain a quantity of a drug, can be coated with a drug, or can be impregnated with a drug. The drug can be or can include at least one of an antibacterial agent, an anti-inflammatory agent, a corticosteroid, and dexamethasone. The first and second tips can be formed from a polymeric composition.

In some embodiments, a shunt for draining fluid built up within a skull of a patient is provided that includes a catheter having an elongate tubular body having proximal and distal ends, first and second flexible tips extending from the distal end of the elongate body and having one or more fluid passageways extending therethrough, a plurality of fluid ports formed in the first and second tips, and a coupling member configured to hold the first and second tips in a position adjacent to one another. The shunt can further include a skull anchor coupled to the proximal end of the elongate tubular body, the skull anchor including an injection port through which fluid can be supplied to or withdrawn from the elongate tubular body. The shunt can further include a drain catheter extending from the skull anchor, and a pressure-actuated valve disposed in line with at least one of the catheter and the drain catheter.

In some embodiments, a method of shunting body fluid is provided that includes inserting a catheter having first and second flexible tips extending from a distal end thereof and coupled to one another into a fluid-containing cavity such that fluid can flow out of the cavity through the catheter, and decoupling the first and second tips such that pulsatile flow of fluid within the cavity causes the first and second tips to strike one another, thereby dislodging obstructions from the first and second tips.

Decoupling the first and second tips can include at least one of removing a sheath disposed around the first and second tips, removing a stylet or cannula disposed around the first and second tips, and exposing a bioabsorbable adhesive disposed between the first and second tips to the fluid. The method can include adjusting a fluid flow rate through a valve in response to an output of a pressure sensor disposed on at least one of the first and second tips.

In some embodiments, a catheter is provided that includes an elongate tubular body having proximal and distal ends and a fluid lumen extending therethrough, and a plurality of flow-indicating projections extending radially inward from an interior surface of the fluid lumen, each of the projections having an imageable portion. At least the imageable portions of the projections can be configured to move relative to the fluid lumen when fluid is flowing through the fluid lumen and to remain stationary relative to the fluid lumen when fluid is not flowing through the fluid lumen.

The projections can each include a first end fixed to the interior surface of the fluid lumen and a second end free to move relative to the interior surface of the fluid lumen. The imageable portions can be disposed at the second free ends of the projections. The projections can be formed by advancing the projections through openings pierced through a sidewall of the elongate tubular body and then sealing the openings. The imageable portions can be formed from a radiopaque material. The imageable portions can be formed from a metallic material. The imageable portions can be formed from a material that is visible under magnetic resonance imaging (MRI). The projections can be flexible. The projections can be disposed throughout the length of the elongate tubular body. The projections can be grouped in one or more clusters formed at discrete locations within the elongate tubular body.

In some embodiments, a method of determining whether fluid is flowing through a fluid lumen of an implanted catheter is provided. The method can include capturing one or more images of the catheter and a plurality of flow-indicating projections extending radially inward from an interior surface of the fluid lumen, each of the projections having an imageable portion. The method can also include determining that fluid is flowing through the fluid lumen when the images indicate that the imageable portions are moving relative to the fluid lumen, and determining that fluid is not flowing through the fluid lumen when the images indicate that the imageable portions are stationary relative to the fluid lumen. The images can be at least one of magnetic resonance images, computed tomography images, positron emission tomography images, and fluoroscopic images.

In some embodiments, a catheter is provided that includes an elongate body having proximal and distal ends and a plurality of independent fluid lumens extending through at least a portion thereof, and a plurality of fluid openings formed in a sidewall of the elongate body, each fluid opening being in fluid communication with one of the plurality of fluid lumens. The fluid openings can be formed such that fluid openings that are in fluid communication with different ones of the plurality of independent fluid lumens face in different directions. The catheter can include a conical tip formed at the distal end of the elongate body, the conical tip having a plurality of fluid openings formed therein, each of the fluid openings being in fluid communication with one or more of the plurality of fluid lumens.

The present invention further provides devices, systems, and methods as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view of a shunt system implanted in a patient;

FIG. 2 is a perspective view of a ventricular catheter and skull anchor;

FIG. 3 is a sectional perspective view of the ventricular catheter of FIG. 2;

FIG. 4 is a perspective view of a ventricular catheter having flexible tips with circular cross-sections;

FIG. 5 is a perspective view of a ventricular catheter with clog-preventing shrouds;

FIG. 6 is a perspective view of a ventricular catheter with a coupling member shown in phantom;

FIG. 7 is a perspective view of a ventricular catheter with a conical tip;

FIG. 8 is a sectional side view of a ventricular catheter with flow-indicating projections disposed therein;

FIG. 9 is a sectional perspective view of a ventricular catheter having flow-indicating projections disposed therein;

FIG. 10 is a perspective view of a ventricular catheter having multiple independent fluid lumens; and

FIG. 11 is a perspective view of a ventricular catheter having a conical tip.

DETAILED DESCRIPTION

Systems and methods are provided herein that generally involve shunting fluid, e.g., shunting cerebrospinal fluid in the treatment of hydrocephalus. Self-cleaning catheters are provided which include split tips configured such that pulsatile flow of fluid in a cavity in which the catheter is inserted can cause the tips to strike one another and thereby clear obstructions. Catheters with built-in flow indicators are also provided. Exemplary flow indicators include projections that extend radially inward from the interior surface of the catheter and which include imageable portions (e.g., portions which are visible under magnetic resonance imaging (MRI)). Movement of the flow indicators caused by fluid flowing through the catheter can be detected using MRI, thereby providing a reliable indication as to whether the catheter is partially or completely blocked.

Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the methods, systems, and devices disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the methods, systems, and devices specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.

FIG. 1 illustrates one exemplary embodiment of a shunt system 100. The system generally includes a ventricular catheter 102, an anchor 104, and a drain catheter 106 with an inline valve 108. In some embodiments, the shunt system 100 can be used to treat hydrocephalus by implanting the ventricular catheter 102 such that a distal end of the catheter is disposed within a brain ventricle 110 of a patient 112. The anchor 104 can be mounted to the patient's skull, beneath the skin surface, and the drain catheter 106 can be implanted such that the proximal end of the drain catheter is disposed within a drain site, such as the abdominal cavity. When fluid pressure in the ventricle exceeds the opening pressure of the valve 108, the valve can be configured to open to allow excess fluid to drain out of the ventricle 110. When the fluid pressure drops to an acceptable level, the valve 108 can be configured to close, thereby stopping further draining of fluid.

It will be appreciated that the arrangement and features of the system 100 shown in FIG. 1 is merely exemplary, and that several other variations are possible. For example, the valve 108 can be disposed distal to the anchor 104 instead of proximal thereto as shown. In other embodiments, the valve 108 can be integral to the anchor 104 or the anchor can be omitted altogether.

As shown in FIG. 2, the ventricular catheter 102 includes an elongate tubular body 114 having proximal and distal ends 114P, 114D. The catheter 102 also includes first and second flexible tips 116 extending from the distal end 114D of the body 114. While two tips 116 are illustrated, it will be appreciated that the catheter 102 can include any number of tips (e.g., three, four, five, six, and so forth). Each of the first and second tips 116 can have one or more discrete or independent fluid passageways extending therethrough. The fluid passageways can remain separate from one another throughout the entire length of the catheter 102, or one or more of the fluid passageways can merge, e.g., at the junction between the first and second tips 116 and the elongate body 114.

A plurality of fluid ports 118 can be formed in each of the first and second tips 116. The ports 118 can be arranged in any of a variety of configurations. For example, the fluid ports 118 can be arranged in a helical pattern through the sidewalls of the first and second tips 116. Alternatively, or in addition, some or all of the fluid ports 118 can be arranged in a linear pattern, in a circular pattern, and/or as open terminal distal ends of the first and second tips 116. In an exemplary embodiment, each of the first and second tips can include one to six fluid ports. The diameter of the fluid ports can be between about 0.1 mm and about 2.5 mm. The cross-sectional area of the fluid ports can be between about 1 mm² and about 3 mm².

One or more of the tips 116 can include an embedded sensor 120. The sensor 120 can include temperature sensors, pH sensors, pressure sensors, oxygen sensors, tension sensors, interrogatable sensors, tilt sensors, accelerometer sensors, glutamate sensors, ion concentration sensors, carbon dioxide sensors, lactate sensors, neurotransmitter sensors, or any of a variety of other sensor types, and can provide feedback to a control circuit which can in turn regulate the drainage of fluid through the system 100 based on one or more sensed parameters. A sensor wire (not shown) can extend from the sensor 120 to an implantable control unit, and/or the sensor can wirelessly communicate the sensor output to an extracorporeal control unit. The embedded microsensor 120 can be a pressure sensor that supplies an output indicative of a pressure in the environment surrounding the first and second tips 116 to the valve 108 to control a fluid flow rate through the valve.

At least a portion of the ventricular catheter 102 (e.g., the first and second tips 116) or any other component of the system 100 can contain or can be impregnated with a quantity of a drug. Alternatively, or in addition, a surface of said portion can be coated with a drug. Exemplary drugs include anti-inflammatory components, anti-bacterial components, drug permeability-increasing components, delayed-release coatings, and the like. In some embodiments, one or more portions of the system 100 can be coated or impregnated with a corticosteroid such as dexamethasone which can prevent swelling around the implantation site and disruptions to the fluid drainage function that can result from such swelling.

As shown in FIG. 3, the first and second tips 116 can each have a D-shaped cross-section. In other words, the first and second tips 116 can each have a substantially planar sidewall 122 and a substantially hemi-cylindrical sidewall 124. The orientation of the D-shape of the first tip can be opposite to that of the second tip, such that the first and second tips 116 together form a circular cross-section when they are coupled to one another or when they longitudinally abut one another. The first and second tips 116 can also have other cross-section shapes. For example, as shown in FIG. 4, the first and second tips 116 can each have a circular cross-section.

The ventricular catheter 102, and in particular the first and second flexible tips 116, can be sized and configured for placement in a brain ventricle. For example, in some embodiments, the body 114 of the ventricular catheter 102 can have a length between about 2 cm and about 15 cm and an outside diameter between about 1 mm and about 5 mm. In some embodiments, the first and second tips 116 can have a length between about 3 cm and about 15 cm and/or a cross-sectional area between about 1 mm² and about 7 mm².

One or more of the fluid ports 118 in the ventricular catheter 102 can include shrouds or covers 126 to reduce the tendency for the port to become clogged. For example, as shown in FIG. 5, the catheter 102 can include shrouds 126 that extend at least partially over the fluid ports 118 formed in each tip 116. In some embodiments, the shrouds 126 can be formed as sections of a hollow sphere, e.g., hollow quarter spheres as shown. The shrouds 126 can have a variety of other shapes, including sections of a cylinder, sections of a cube, and so forth. The shrouds 126 can be placed in any of a variety of orientations. For example, the shrouds 126 can be placed in random orientations, in alternating orientations, in a repetitive sequence of orientations, and so forth. In operation, the shrouds 126 can prevent ingrowth of choroid plexus into the fluid ports 118 and/or accumulation of other tissue, debris, or material that might block the fluid ports.

As shown in FIG. 6, the ventricular catheter 102 can include a coupling member 128 configured to hold the first and second tips 116 in a position adjacent to one another, e.g., in longitudinal abutment with one another. The coupling member 128 can be disposed around the first and second tips 116 as shown, and thereby configured to retain the tips in a position proximate to one another. Exemplary coupling members 128 can include a seamlessly removable insertion sheath, a peelable sheath, a stylet, or a cannula disposed around the first and second tips 116 and accessible for removal from a proximal end of the catheter 102. The coupling member can also be in the form of an adhesive disposed between the first and second tips 116. For example, in the case of D-shaped tips 116, the planar sidewalls 122 of the first and second tips can be adhered to one another. The adhesive or at least the adhesive strength thereof can be configured to degrade when the adhesive is exposed to conditions within the body of a patient (e.g., certain temperatures, pHs, chemical compositions, and so forth). In exemplary embodiments, the adhesive is biocompatible and bioabsorbable and configured to rapidly degrade when exposed to cerebrospinal fluid in a patient's ventricle. Exemplary adhesives include, e.g., polylactides, polyglycolides, polylactones, polyorthoesters, polyanhydrides, proteins, starches, sugars and copolymers and/or combinations thereof.

The distal-most tip of the catheter 102 can have a variety of shapes and configurations. For example, the distal ends of the first and second tips 116 can be open or closed, or can be primarily closed with one or more openings formed therein. By way of further example, the distal ends of the first and second tips 116 can together form a section of a sphere (e.g., as shown in FIG. 2), can be straight cut to form a blunt end (e.g., as shown in FIG. 6), can be slash cut, or can form a section of a cone (e.g., as shown in FIG. 7).

The ventricular catheter 102 can include various features for indicating whether or to what degree fluid is flowing through the catheter. Such features can advantageously allow for accurate detection or confirmation of blockages or reduced flow conditions within the catheter 102, without requiring removal of the catheter. For example, as shown in FIG. 8, the catheter 102 can include a plurality of flow-indicating projections 130 disposed therein. The projections can be formed from any of a variety of flexible materials to allow them to flex or bend. The projections can extend radially inward from an interior surface 132 of a fluid lumen of the catheter 102, such that a first end 134 of each projection 130 is fixed to the interior surface 132 and a second end 136 of each projection is free to move relative to the interior surface when the projection flexes or bends.

The projections 130 can be imageable or can include one or more imageable portions. For example, the projections 130 can include imageable portions 138 disposed at the second free ends 136 of the projections. The imageable portions 138 can be visible under one or more imaging techniques, such as magnetic resonance imaging (MRI), computed tomography (CT) imaging, positron emission tomography (PET) imaging, and fluoroscopic imaging. The imageable portions 138 can thus be formed from a radiopaque material, a metallic material, a material that is visible under magnetic resonance imaging, or any of a variety of other materials visible under the imaging techniques listed above. As shown in FIG. 9, in some embodiments, the entirety of each projection 130 can be imageable.

The projections 130 can be coupled to the catheter 102 by piercing the projections through a sidewall of the catheter and advancing the projections through the pierced opening. The opening can then be sealed using any of a variety of sealing compounds, including silicone glue or other adhesives.

The projections 130 can be disposed throughout the length of the catheter 102 (e.g., in the elongate tubular body 114 and/or the distal tips 116 of the catheter), or can be grouped in one or more clusters formed at discrete locations within the catheter. The density of the projections 130 (e.g., the number of projections disposed in a given surface area of the interior of the catheter) can be selected based on the size of the fluid lumen in which the projections are disposed.

In use, at least the imageable portions 138 of the projections 130 can be configured to move relative to the fluid lumen when fluid is flowing through the fluid lumen and to remain stationary relative to the fluid lumen when fluid is not flowing through the fluid lumen. The projections 130 can thus act as reef or thread-like structures that sway back and forth as fluid flows through the catheter 102. This movement of the projections 130 can be observed using the imaging techniques listed above to assess whether and to what degree fluid is flowing through the shunt system 100.

FIG. 10 illustrates another exemplary embodiment of a ventricular catheter 202. Except as indicated below, the structure and operation of the catheter 202 is identical to that of the catheter 102 described above, and therefore a detailed description thereof is omitted here for the sake of brevity. Instead of multiple flexible tips, the catheter 202 includes a single tip 216 with a plurality of independent fluid lumens 240 extending therethrough. The fluid lumens 240 can remain independent throughout the length of the catheter 202, or can merge into one or more common fluid lumens at a location spaced a distance from the distal end of the catheter. While three fluid lumens 240 are shown, it will be appreciated that virtually any number of fluid lumens can be included. For example, the catheter 202 can include between two and five fluid lumens 240. Each of the independent fluid lumens 240 can include one or more fluid openings 218 formed in a sidewall thereof through which fluid to be shunted can flow into the fluid lumens. The distal ends of the fluid lumens 240 can be open as shown, or can be fully or partially closed. In some embodiments, the distal end of the catheter 202 can form a section of a sphere or cone 242, e.g., as shown in FIG. 11, which can have one or more fluid openings 218 formed therein. Provision of multiple independent fluid lumens 240 can advantageously provide redundancy in the event that one or more of the fluid lumens becomes clogged. Further, if the source of clogging is directional, i.e., the source arrives at the catheter in predominately one direction, then it is more likely that if one lumen becomes clogged, the other lumens will continue to operate as the openings leading into those lumens will be facing in different directions from the lumen that became clogged. Also, providing multiple fluid lumens 240 allows for a flow rate comparable to that of a single lumen catheter while permitting the cross-sectional area of each fluid lumen 240 to be made small as compared to a single lumen catheter. The smaller dimensions of the multiple lumens 240 can prevent foreign material or choroid plexus ingrowth from entering the lumen and thereby reduce the potential for clogging.

The catheters 102, 106, 202 and the coupling member 128 can be formed from any of a variety of materials, including polymeric compositions, parylene compositions, silastic compositions, polyurethane compositions, PTFE compositions, silicone compositions, and so forth.

Referring again to FIGS. 1 and 2, the system 100 can include an anchor 104 to which the ventricular catheter 102 can be coupled. The anchor 104 can be secured to the patient's skull, beneath the skin, to secure the proximal end of the ventricular catheter 102 and to provide access to the system 100. For example, the anchor 104 can include a reservoir in fluid communication with the ventricular catheter 102 and covered by a septum 144. A needle can be used to pierce the skin and the septum 144 and supply fluid to the reservoir and to extract fluid from the reservoir. Fluid communication between the reservoir and the patient's ventricle 110 via the ventricular catheter 102 can be used to inject one or more drugs, therapeutic agents, etc. into the ventricle. In embodiments in which the catheter 102 includes multiple independent lumens, one or more lumens can be dedicated for drug delivery to the ventricle 110 while one or more other lumens can be dedicated for fluid drainage from the ventricle.

In the illustrated embodiment, the anchor 104 is substantially disk-shaped and includes a concave distal surface 146 configured to substantially conform to the contour of the patient's skull. The proximal surface 148 of the anchor 104 can include a retaining ring 150 that extends around the circumference of the anchor and holds the septum 144 in place. The ventricular catheter 102 can couple to a center point of the distal surface 146. A drain catheter 106 can extend laterally out from the anchor 104 to the downstream valve 108 and, ultimately, to the drain site. The anchor 104 can thus provide a rigid coupling between one or more implanted catheters 102, 106 and facilitate a 90 degree turn in the fluid path out of the ventricle 110.

The drain catheter 106 extending out of the anchor 104 can be coupled to a valve 108 configured to selectively open to release fluid from the ventricle 110. In general, the valve 108 can include an inlet port, an outlet port, and a biased flapper disposed therebetween. When pressure exceeds the bias strength of the flapper, the flapper can open to allow fluid communication between the inlet port and the outlet port. The valve 108 can also be adjustable, e.g., via an externally-applied magnetic field. Shunt valves with adjustable pressure settings are well known in the art, and are disclosed for example in U.S. Pat. No. 3,886,948, issued on Jun. 3, 1975 and entitled “VENTRICULAR SHUNT HAVING A VARIABLE PRESSURE VALVE,” the entire contents of which are incorporated herein by reference.

The valve 108 can be disposed inline relative to the drain catheter 106, e.g., such that a first portion of the drain catheter 106 is fluidly coupled to the inlet port of the valve 108 and a second portion of the drain catheter 106 is fluidly coupled to the outlet port of the valve 108. The drain catheter 106 can thus be conceptualized as two separate catheters, one extending between the anchor 104 and the valve 108 and another extending between the valve and the drain site. The drain catheter 106 can extend such that its proximal end is disposed within a drain site in the patient's body, e.g., the abdominal cavity. The drain catheter 106 can be a traditional cylindrical catheter having a single fluid lumen extending therethrough. Alternatively, the drain catheter 106 can include a plurality of discrete fluid lumens extending along at least a portion of its length. The proximal end of the drain catheter 106 can have a split-tip design and/or can otherwise be configured in the same manner as the distal end of the ventricular catheters 102, 202 described above.

In use, the shunt system 100 can be used to transfer fluid from one location to another location. When used in a patient's body, the shunt system 100 can be used to treat any of a variety of diseases, conditions, or ailments. For example, the system 100 can be used to treat hydrocephalus and/or to shunt fluid built up within a patient's skull by implanting the ventricular catheter 102 such that a distal end of the catheter is disposed within a brain ventricle 110 of the patient 112. The anchor 104 can be mounted to the patient's skull, beneath the skin surface, and the drain catheter 106 can be implanted such that the proximal end of the drain catheter is disposed within a drain site, such as the abdominal cavity.

Once the distal end of the ventricular catheter 102 is disposed within the ventricle 110, the coupling member 128 can be removed (or permitted to degrade in the case of an adhesive) to decouple the first and second tips 116 from one another and allow the tips to separate. As noted above, the coupling member 128 can be or can include a peelable sheath, a stylet, or a cannula which can be accessible for removal from a proximal end of the catheter 102. In other words, the coupling member 128 can be pulled proximally by a surgeon or other user to remove the coupling member once the distal tip of the catheter 102 is placed in the desired location.

Once decoupled, pulsatile flow of fluid within the ventricle 110 can be effective to cause the first and second tips 116 to strike one another. The forces applied to the tips 116 as a result of such striking can dislodge obstructions from the first and second tips or the fluid ports 118 or passageways thereof, thereby preventing, reducing, or alleviating clogs. It will be appreciated that the relatively continuous pulsatile flow of fluid can persist throughout the term of treatment, providing an automatic self-cleaning and anti-clogging functionality.

As in a typical shunt system, when fluid pressure in the ventricle 110 exceeds the opening pressure of the valve 108, the valve can be configured to open to allow excess fluid to drain out of the ventricle. When the fluid pressure drops to an acceptable level, the valve 108 can be configured to close, thereby stopping further draining of fluid. In some embodiments, the output of a sensor 120 (e.g., a pressure sensor) disposed in or on one of the first and second tips 116 can be used to control operation of the valve 108. For example, an opening pressure, fluid flow rate, or other property of the valve 108 can be adjusted in response to the output of a pressure sensor 120.

In embodiments which include flow indicating features 130, a determination can be made as to whether or to what degree fluid is flowing through the fluid lumen. For example, one or more images (e.g., MRI, CT, PET, or the like) of a catheter 102 and a plurality of flow-indicating projections 130 disposed therein can be captured. An observer can then view the images and determine whether and to what degree the projections 130 are moving. For example, when the images indicate that the imageable portions 138 of the projections 130 are moving relative to the fluid lumen, it can be determined that fluid is flowing through the fluid lumen. Likewise, when the images indicate that the imageable portions 138 are stationary relative to the fluid lumen, it can be determined that fluid is not flowing through the fluid lumen and that there may be a blockage or obstruction in the shunt system.

Although the invention has been described by reference to specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims. 

What is claimed is:
 1. A catheter for shunting fluid built up within a skull of a patient, comprising: an elongate tubular body having proximal and distal ends; first and second flexible tips extending from the distal end of the elongate body and having one or more fluid passageways extending therethrough; a plurality of fluid ports formed in the first and second tips; and a coupling member configured to hold the first and second tips in a position adjacent to one another.
 2. The catheter of claim 1, wherein the first and second flexible tips are sized and configured for placement in a brain ventricle.
 3. The catheter of claim 1, wherein the coupling member comprises a peelable sheath disposed around the first and second tips.
 4. The catheter of claim 1, wherein the coupling member comprises a seamlessly removable insertion sheath disposed around the first and second tips.
 5. The catheter of claim 1, wherein the coupling member comprises a bioabsorbable adhesive disposed between the first and second tips.
 6. The catheter of claim 1, wherein the coupling member comprises a stylet or cannula disposed around the first and second tips.
 7. The catheter of claim 1, wherein the first and second tips each have a D-shaped cross-section.
 8. The catheter of claim 7, wherein the first and second tips together form a circular cross-section when coupled to one another by the coupling member.
 9. The catheter of claim 1, wherein the first and second tips each have a circular cross-section.
 10. The catheter of claim 1, wherein the plurality of fluid ports are formed in a helical pattern through sidewalls of the first and second tips.
 11. The catheter of claim 1, wherein pulsatile flow of fluid in which the first and second tips are disposed is effective to cause the first and second tips to strike one another, thereby dislodging obstructions from the first and second tips.
 12. The catheter of claim 1, further comprising a plurality of shrouds, each shroud being disposed over a respective one of the plurality of fluid ports.
 13. The catheter of claim 12, wherein the plurality of shrouds are formed as hollow quarter spheres.
 14. The catheter of claim 1, wherein at least one of the first and second tips includes an embedded microsensor.
 15. The catheter of claim 14, wherein the embedded microsensor comprises at least one of an interrogatable sensor, a pressure sensor, a tilt sensor, an accelerometer sensor, a glutamate sensor, a pH sensor, a temperature sensor, an ion concentration sensor, a carbon dioxide sensor, an oxygen sensor, and a lactate sensor.
 16. The catheter of claim 14, wherein the embedded microsensor is a pressure sensor that supplies an output indicative of a pressure in the environment surrounding the first and second tips to a valve to control a fluid flow rate through the valve.
 17. The catheter of claim 1, wherein at least one of the first and second tips contains a quantity of a drug, is coated with a drug, or is impregnated with a drug.
 18. The catheter of claim 17, wherein the drug comprises at least one of an antibacterial agent, an anti-inflammatory agent, a corticosteroid, and dexamethasone.
 19. The catheter of claim 1, wherein the first and second tips are formed from a polymeric composition.
 20. A shunt for draining fluid built up within a skull of a patient, comprising: the catheter of claim 1; a skull anchor coupled to the proximal end of the elongate tubular body, the skull anchor including an injection port through which fluid can be supplied to or withdrawn from the elongate tubular body; a drain catheter extending from the skull anchor; and a pressure-actuated valve disposed in line with at least one of the catheter and the drain catheter.
 21. A method of shunting body fluid, comprising: inserting a catheter having first and second flexible tips extending from a distal end thereof and coupled to one another into a fluid-containing cavity such that fluid can flow out of the cavity through the catheter; and decoupling the first and second tips such that pulsatile flow of fluid within the cavity causes the first and second tips to strike one another, thereby dislodging obstructions from the first and second tips.
 22. The method of claim 21, wherein said decoupling comprises at least one of removing a sheath disposed around the first and second tips, removing a stylet or cannula disposed around the first and second tips, and exposing a bioabsorbable adhesive disposed between the first and second tips to the fluid.
 23. The method of claim 21, further comprising adjusting a fluid flow rate through a valve in response to an output of a pressure sensor disposed on at least one of the first and second tips. 24-37. (canceled) 